The importance of integrated circuit semiconductors in the electronic industry is well known. These circuits have revolutionized the industry. Employed in miniaturized form and made into chips, these circuits can be utilized in great numbers in very little space, such as on printed circuit boards.
Integrated circuits (IC) are commonly packaged by mounting the semiconductor chip on a rectangular substrate or carrier having conductive elements on one side which extend from the chip to the marginal edge of the substrate. In order to connect the chip carrier to the printed circuit board an electrical connector is employed which provides electrical connection between the conductive elements of the chip carrier and conductive traces of the printed circuit board. Such chip carrier connectors are shown for example in U.S. Pat. Nos. 4,378,139; 4,220,383; and 4,381,131.
Typically, these connectors include a rectangular (usually square) body or housing which supports, around the permetrical edge thereof, a plurality of spring contacts. The chip carrier is receivable into the body, and the conductive elements thereon engage the spring contacts. The contacts include extending portions which connect to the conductive traces in the printed circuit board. In order to provide adequate electrical connection between the chip carrier and the spring contacts, it is necessary to provide some means to assure that the spring contacts will be continuously urged against the conductive elements of the chip carrier with a force sufficient to maintain such electrical contact.
Devices commonly used to maintain such electrical contact are lids which are moved to bear against the chip carrier and urge it into resilient electrical contact with the spring contacts. These lids, typically hinged at one end of the body, may also include a separate spring element to further bear against the chip carrier. Such hinged lids are shown, for example, in the above-mentioned U.S. Pat. Nos. 4,378,139 and 4,220,383.
When employing a chip carrier of conventional dimensions, the carrier may include a great number of conductive elements or traces thereon. Each element would individually contact a corresponding one of an identical number of spring contacts in the connector. Each spring contact exerts a force against the connector upon insertion. The force may vary from contact to contact depending on construction, thickness and material composition. With contacts numbering in the range of 48 to 68 or lower, only a relatively light force is needed to urge the chip carrier into electrical connection with the contacts. However, when the number of conductive elements of the chip carrier, and correspondingly the number of contacts in the connector is increased to as many as 132 or more, as is now desired for increased capacity, the force needed to urge the chip carrier into engagement with the contacts is greatly increased. In fact, the applied force needed may be so great as to render insertion by the user difficult.
Hinged lids or levers would of course reduce the difficulty of insertion as the lever aids in rendering a greater applied force to the carrier upon closing, based on simple lever principles. However, to provide an effective applied force sufficient to close the lid and urge the carrier into engagement with the contacts, the length of the lid would have to be greater then that which is acceptable for the space provided.
It is accordingly desirable to provide an urging mechanism which would provide sufficient effective force to the chip carrier and yet be of an acceptable size.